1. Field of the Invention
This invention relates generally to wireless local area networks, and in one example, to mobile wireless local area networks used to interrelate individual mobile nodes. In one embodiment, this invention relates to wireless local area networks having the capability of automatically establishing and/or modifying functionality of a network in response to the characteristics and/or identity of the nodes connected to the network at a given time.
2. Description of the Related Art
Local area networks (“LANs”) allow a group of devices (e.g., computers, workstations, printers, file storage devices, and other devices) to communicate and exchange information and share resources over a limited area using a pre-determined software protocol. Each device connected to the LAN may be referred to as a “node.” The nodes communicate using a software protocol, which is an electronic method of communicating using a formal set of conventions governing the format and relative timing of electronic messages exchanged between nodes in the LAN.
In the past, LANs have utilized hardwire connections with hardware interfaces that allow individual devices or nodes to access the network. Within each node, an executable software program interprets the signals transmitted on the network between the nodes. Individual nodes of a hardwired LAN may be moved and connected to a new wired network of a like kind, thus becoming part of a new LAN. However, disconnecting and reconnecting hardware components of a LAN is often inconvenient and time consuming.
Just one example of an application for a LAN is for interrelating sensor and/or control devices employed when performing well treatments, such as well stimulations. Such well treatments are typically performed in the field using mobile vehicle mounted equipment, including pumps, vessels, mixing equipment, etc. The number and characteristics of individual components of such equipment is typically dependent on factors such as the size and type of the well treatment job to be performed. Individual components of the mobile equipment are typically assembled and connected with flowlines at the wellsite. Hardwire communication and data lines are typically employed to transmit voice and data (e.g., sensor readings and control signals) between individual nodes. In this capacity, treatment conditions (e.g., pumping pressures, volumes pumped, and temperatures) may be monitored and/or recorded, while treatment control parameters (e.g., pumping rate and mixing volumes) may be automatically and/or remotely controlled in response to measured treatment conditions. In one example, treatment conditions may be monitored for safety concerns (such as over pressure conditions) and the necessary control steps may be automatically taken to address the safety concerns (such as pump shut-down).
Although LANs may be used to provide increased control and efficiency to well treatment operations, a large number of wires or cables are typically required to be brought to the wellsite and strung between individual pieces of vehicle-mounted equipment prior to a job, and removed thereafter. This is typically a time consuming and manpower-intensive process. Reliability of such hardwired connections may also be less than desired. Furthermore, each well treatment may be unique, requiring different types of nodes, equipment, and combinations thereof, to communicate and exchange data. As a result, individual nodes of a LAN must typically be reconfigured, modified, and/or replaced according to the characteristics of the equipment combination employed for a given job. This is also typically a time-consuming and manpower intensive process. For example, well servicing equipment nodes in a LAN at a wellsite location often require changes in the system configuration when reconfiguring the equipment or adding nodes to the LAN. Once again, this may also require time-consuming intervention on the part of a service engineer (e.g., field technician, network administrator, etc.).
Hardware and software has now evolved so that network communication between two or more devices in a LAN may now be by wireless communication, such as using optical transmission or radio frequency (RF) broadcast. The use of wireless communications simplifies movement and connection of such devices. A wireless LAN may be established when two or more devices with compatible wireless communication hardware and software are within communication range. In a typical wireless LAN, a “master” or “base” node is used to orchestrate communication between individual nodes. Individual nodes may be moved while maintaining contact with the network, or nodes may re-establish contact with the network when contact between nodes is lost.
Wireless LANs solve some of the problems encountered with traditional LANs because hardwired connections are not required. However, existing wireless networks typically operate with strict limitations as to the communication protocol and network functionality. Because devices communicating in a wireless LAN have set and defined functionality, changes to network set-up and modifications or substitutions of devices are often required when configuring a wireless LAN at a new location.